Question
a) By which of the following are elements ordered in the modern periodic table? relative formula mass mass number atomic number
Answer
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(297 Votes)
Quilla
Elite · Tutor for 8 years
Answer
Atomic number.
Explanation
In the modern periodic table, elements are ordered according to a very specific trend which refers to their atoms' numbered properties. Let's dissect each given option:1. 'Relative formula mass’ is the average mass of a formula unit, which is an average of all the isotopes that make up an element. However, this quality is not taken as the basic characteristic for ordering elements on the periodic table.2. `Mass number’ is the number of protons plus number of neutrons within the nucleus of an atom. However, it turns up to be somewhat problematic when trying to order elements using this factor, especially when you consider isotopes that have the same mass numbers but different atomic numbers.3. 'Atomic number’ is the distinct characteristic of each element - it directly defines the number of protons in an atom's nucleus and therefore identifies the unique identity an atom has.Interestingly, the arrangement of elements on the modern periodic table was initially ordered according to atomic weight. However, the British scientist Henry Moseley discovered that a more accurate organization could be achieved by arranging elements according to atomic number. This was because he found that atomic number better defines each distinct elements and their properties than using atomic weights. Therefore the correct and foundational manner elements have been set upon the modern periodic table is by using the attribute- atomic number.